[R] add points to lattice cloud plot (3D scatter)

[Duncan Murdoch]

On 28/02/2019 5:39 a.m., Luigi Marongiu wrote:
> Dear all,
> is it possible to add points to a lattice cloud plot (3D scatter)? I
> can plot the main data, but what if I wanted to add another point. In
> R there is the high level plotting function plot(), then the low level
> points() or lines() etc. What is the equivalent for lattice?

I don't know for sure, but I don't think you can do that in lattice. 
The scatterplot3d::scatterplot3d function returns enough information to 
do this, but I don't think lattice::cloud does.  But even 
scatterplot3d::scatterplot3d won't necessarily get it right if points 
hide others that are behind them.  It uses the "painter's algorithm", 
and that needs everything to be drawn in just the right order, which you 
probably won't get if you draw things in several calls.

You can draw things in arbitrary order using rgl::plot3d or related 
functions, but you'll need to do more work yourself to get an array of 
plots like lattice gives.

Duncan Murdoch


> 
> Thank you
> 
> 
>>>>
> 
> df = data.frame(Name = c("A", "B", "C", "D", "E"),
>                x_axis = c(-0.591, 0.384, -0.384, -0.032, 0.754),
>                y_axis = c(-1.302, 1.652, -1.652, 0.326, 0.652),
>                z_axis = c(1.33, 1.33, 2.213, 0.032, -0.754),
>                stringsAsFactors = FALSE)
> 
> cloud(z_axis ~ x_axis * y_axis, data = df,
>        xlab = "X", ylab = "Y", zlab = "Z",
>        pch = 16, col = "red", type = "b", cex = 1.5,
>        ltext(x=df$x_axis, y=df$y_axis, z=df$z_axis,
>              labels=df$Names, pos=1, offset=1, cex=0.8)
> )
> 
> df2 = data.frame(Name = "F",
>                  x_axis = 0.891,
>                  y_axis = 2.302
>                  z_axis = -1.83,
>                  stringsAsFactors = FALSE)
>